Three were easy, because they were entirely in the computer - total minor league innings pitched by pitchers who debuted in 2004, 2005, and 2006 (includes any and all minor league innings pitched in the year they made their major league debut).
Then I dug out a 1974 Baseball Register I have, and, far more slowly, did the same for all pitchers who made their major league debut in 1973.
For the recent years the numbers were:
2004 averaged 137 minor league games and 433 innings (113 pitchers)
2005 109 games and 353 innings (100 pitchers)
2006 130 games and 434 innings (134)
Bounce to the old stuff:
1973 85 games and 420 innings (53 pitchers)
Fewer games, essentially equal innings, unless 1973 was as fluky within its own time as 2005 appears to have been in ours. The distribution is different. There were three 1973 pitchers who entered the majors with zero minor league innings - Ed Bane, David Clyde, and Dick Ruthven. There were a bunch of guys under 200 - Jim Crawford only had 97; Rich Troedson only had 124, Randy Jones 140, Eduardo Rodriguez 148, Larry Christensen 138. Lots of pitchers had 200-inning seasons in the minors, something unheard of now (Tim Kalita is the last one in my database, 200 innings for Erie in 2001, at least for any one team). There certainly were some with 700, even some we’ve heard of. Wayne Garland had 730, John Montague 840, Dick Pole 713, John D’Acquisto 709. But the average was 420; the median was even lower, at 379 (Jim Kremmel, who was once traded for Ron Santo).
I also looked up a few who didn’t debut in 1973 but were in the book. Jim Palmer had 129 minor league innings before his debut, Tom Seaver 210, Don Sutton 249, and Catfish Hunter zero, nada, nil. Fergie Jenkins was on the high side at 546. Nolan Ryan, cited by Buzz as one who thinks pitchers don’t spend enough time in the minors, 294. Gaylord Perry had 883, one for Buzz. Gossage 238. Cuellar 376.Tanana 349. Richard 338. Koosman 289. Al Downing probably will get a few mentions this month and next - debuted after 98 innings. Sparky Lyle 250. Lolich 548. Don Gullett 78. Larry Gura 149.Tom Hall 336.
Good pitchers have never spent much time in the minors, no matter what Tony LaRussa told Buzz.